Receiving system for radiant energy



June 3 1924.

J. H. HAMMOND, JR

RECEIVING SYSTEM FOR RADIANT ENERGY Filed Oct; 1% 1917 3 Sheets-Sheet 1 2 Mam 5? ITECE/VEI? INVENTOR I I W H/' A TTORNE Y June 3, 1924 J. H. HAMMOND, JR

RECEIVING SYSTEM FOR RADIANT ENERGY Filed Oct. 17

1917 5 Sheets-Sheet 2 GRID mL TA GE ...&

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H/s ATTORNEY- June 3, 19246 1,496,311

J. H. HAMMOND, JR

RECEIVING SYSTEM FOR RADIANT ENERGY FiledOct. 17 1917 3 Sheets-Sheet. 3

241 i 250 l PM 3 IM/EA/TGI? I775 ATTORNEY aten teddune 3, 1924.

JOHN HAYS HAMMOND, JR, 0E GLOU'CESTER MASSACHUSETTS.

RECEIVING SYSTEM FOR RADIANT'ENERGY.

I Application filed October 17, 1917. Serial No. 197,127.

T 0 all whom it may concern:

Be it known that 1, JOHN HAYS HAM- MOND, J r., a citizen of the United States, and a resident of Gloucester, in the county of Essex and State of Massachusetts,-have invented certain new and useful Improvements in Receiving Systems for Radiant Enorgy, of which the following is aspecification.

In the operation of some ofthe receiving systems for radiant energy which have been heretofore designed for use upon a torpedo for steering the torpedo from a distance, it has been found that the receiving system some times fails to respond properly to the signals from a distant station when the torpedo is in close proximity to a hostile station which is transmitting powerful signals or shocks 'for thepurpose of interfering with the control of the torpedo from the distant station. It has been found that this failure on the part of the receiving system to respond properly to the signals from a distant control station is sometimes due mainly to a smothering or saturating effect which is produced by the powerful signals from the hostile station, which prevent the weaker signals from the distant control station from having any appreciable effect upon the receiving system. 7

One of the objects of this invention, therefore, is to provide a receiving system, which will not be liable to be smothered or sat- 'urated by signals transmitted from a hostile station. Other objects of this invention are to provide an improved detector, and to will appear hereinafter.

In the accompanying drawings, Fig. 1 is a diagrammatic side elevation of a receiving system including an ordinary gaseous detector such as is sometimes provided in receiving systems of radiant energy which are used in controlling torpedoes; Fig. 2 is a diagram explanatory of the operation of the detector shown in Fig. 1; Fig. 3 is a diagrammatic side elevation of a receiving system constructed in accordance with this invention; Figs. 4 and 5 are diagramsexplanatory of the o eration of the receiving system shown in Fig. 3; and Figs. 6 and 7 are diagram- -inatic side elevations respectively of two modifiedreceiving systems constructed inaccordance with this invention.

The ordinary receiving system, shown in Fig. 1, comprises a gaseous detector 9. of any The detector 9 is arranged to control a plate or wingcircuit 20, which connects the plate or terminal 11 with one end of the filament 13, and which is arranged to be energized by a battery 21 and to control a receiving instrument 22 or other device. The detector 9 is usually arranged to be controlled by a closed oscillatorycircuit, including a variable condenser 25-and acoil 26, one end of which is connected by a conductor 27 to the grid 12, and the other end of which is connected by a conductor 28 to one end of the filament 13.

In the form of receiving system shown in Fig. 1, the coil 26 is inductively connected to a coil 29 which forms part of an'open aerial circuit, including an antenna 30 and being grounded through the coil 29 as at 31.

In the ordinary arrangement. of receiving system shown in Fig. 1, the effect of an incomingsignal received by the open aerial circuit 30, 29, 31 is to cause the potential of the grid 12 to fluctuate with respect to the potential of the filament 13, and thereby to cause corresponding fluctuations in the current which is normally flowing in the controlled circuit through the bulb 10, the bat tery 21 and the controlled instrument or device 22.

A characteristic plate current-grid voltage curve 10 showing diagrannnatically the operation of the ordinary gaseous detector 9 appears in Fig. 2 in which the curve 40 is plotted from two full lines 41 and 42 which.

form a right angle, and along one of which, 41, the current flowing through the plate or controlled circuit 11, 20, 22, 21, 13. is meas ured, and along the other of which, 42, the voltage on the grid 12 is measured. In prac tice, the voltage of the grid 12 is adjusted to be normally either approximately as indicated by the point where the dotted line 45 intersects the full line 42, or approximately as indicated by the point where the dotted line 46 intersects the full line 42, with correspondin normal currents indicated respectively y the points where the dotted lines 47 and 48 intersect the full line 11.

In other Words, the voltage of the grid is ad'usted approximately either at the voltage in icated by one of the humps of the characteristic curve 610, or approximately at the voltage indicated by the other hump. of the characteristic curve 40. The efiect of an incoming signal in either case is to cause a symmetrical fluctuation of the potential of the rid 12 on either side of its normal potent1al, and such symmetrical fluctuations of the voltage of the grid cause unsymmetrical fluctuations of the current in the controlled circuit 20, 21 of the detector.

Such unsymmetrical current fluctuations are in efiect rectifying actions, and when the grid 12 is normally adjusted at the lower initial voltage indicated by the line 15 of Fig. 2, an incoming signal of radiant energy acts upon the detector 9 to cause a net increase in the current through the detector and the controlled circuit 20, 22, 21, While when the grid 12 is normally set at a higher initial voltage indicated by the line 46 of Fig. 2, an incoming signal acts upon the detector to cause a net decrease in the current through the detector and the controlled circuit 20, 22, 21. I

In either case, as the strength of the incoming si nal is increased, the current fluctuations t rough the detector and the controlled circuit 20, 22, 21 will eventually reach a limit imposed by the ditl'erence between the minimum and the maximum current indicated by the characteristic curve 40 of the detector. A further increase in the signal strength beyond this limit will no longer cause a correspondin net change in the current of the controlle circuit 20, 22. 21.

When the gaseous detector is in this condition, due for instance to forcible interference, it is evident that any weaker signal of radiant energy received at the same time cannot truly manifest itself in a corresponding change in the current of the controlled circuit 20, 22, 21, and hence could not Well be picked out by even the most selective tuning devices operating from or controlled by the receiving device 22 of the controlled circuit 20, 22, 21. In other words, when the gaseous detector 9 is in this smothered or saturated condition, it cannot'faithfully reveal in the current fluctuations of the controlled circuit 20, 22, 21, all the potential fluctuations of the incoming signals.

This invention provides a system in which the arrangement is such that it is extremely diliic'ult, if not impossible, to smother or saturate the system through the action of powerful incommg signals from a relatively near interfering station in such a manner as to prevent the system from being properly responsive to the weaker signals from the distant control station. In one form of syseeann constructed as hereinbefore described, are

arranged to be simultaneously controlled in any suitable manner and to act in unison to control a suitable receiving instrument or any desired arrangement of tuned receiving circuits.

For instance, as shown inFFig. 3, three detectors 100, 101', 102, may be arranged in accordance with this invention, to be controlled simultaneously by a closed oscillatory circuit including a variable condenser 105 and a coil 106. The coil 106 forms the secondary of a transformer 107, which has a primary coil 108 connected in series with an antenna 109 which is grounded through the coil 108 at 110. .One end of the secondary coil 106 of the closed oscillatory circuit 105, 106-, is connected by a conductor to the three grids 12 of the detectors 100, 101, 102, and the other end of the secondary coil 106 is connected by a conductor 121 to one end of the filament 13 of the first detector 100, which in turn is connected by a conductor 122 to one pole or a battery 123, the other pole of which is connected by a conductor 124 to one end of the filament 13 of the second detector 101. This second filament 13 is connected in turn by a conductor 125 to one pole of a battery 126, the other pole of which is connected by a conductor 127 to one end of the filament 13 of the third detector 102. This latter filament 13 is connected by a conductor 128 to one pole of a battery 129 which is in a controlled circuit which includes a receiving device 130, and a conductor 131 connected to the three plates 11 of the three detectors ill from each other in progressively increasing amounts.

The three characteristic plate current-grid voltage curves 150, 151 and 152 of the three separate detectors 100, 101 and 102 arranged as shown in Fig. 3, are shown in Fig. 4, in which the curves are plotted from two straight full lines 153 and 154 which meet to form a right angle. and along one of which 153, grid voltages are'nieasured', and along the other of which, 154, plate currents are measured. The characteristic plate current-grid voltage curve of the three detectors 100, 101 and 102 acting in unison would be the resultant of the superposition of the plate current-grid voltage curves 150, 151 and 152 or? the separate detectors, as

shown in Fig. 5, in which the characteristic resultant curve 160 is plotted from the straight lines 161 and 162 meeting in the form of a right angle, and along oneof which, 161, grid volta e is measured, and along the other of whic li, 162, plate current is measured.

From-the foregoing, it is evident that in this improved system shown in Fig. 3, and just described, a much wider current variation in the plate or controlled circuit through the receiving device 130 is possible than in the ordinary arrangement shown in Fig. 1 in which the receiving device 22 is controlled by a single detector, and that the difierence between the maximum current possible and the minimum current obtainable in the controlled circuit including the receivin device 130 of this improved system, depen s upon and is directly proportional to the number of detectors 100, 101, 102 utilized in the system to control the receiving device 130.

lit is also evident that by increasing the number of detectors this difference between the limits of the current strength in the plate or controlled circuit may be propor tionally increased, and that by using a suitable number of detectors arranged as shown in Fig. 3, the capacity of the system may be so enlarged that it will be able to absorb powerful interfering signals from a nearby station without becoming saturated or smothered and without having the controlled circuit 129, 130 and 131 including the receiving device 130, become conse:

a plate 202, a grid 203 and aplurality of filaments, for instance. three. 204, 205 and 206. This multiplex detector 200 is arranged to be controlled by a closed oscillatory circuit 210, which includes a variable condenser 211, and a coil 212. The coil 212 forms the secondary coil of a transformer 213 which includes a primary coil 214 connected in serles wlth an antenna 215 which is grounded through the coil 214 at 216. ()ne end of.

the secondary coil 212 is connected by a conductor 220 to thegrid 203, and the other end of the secondary coil 212 isconnected by a conductor 221 with one end of the first filament 204, which in-turn is connected by a conductor 225 to one .pole of. abattery 226, the other pole of which is connected by a conductor 227 to one end of the second filament 205. The second filament 205 is connected by a conductor 228 with one pole one side of a closed oscillatory circuit 238,

which includes a primary coil 239 and a variable condenser 240, and the other side of which is connected by a conductor 241 to the plate 202 of the multiplex detector 200. The three filaments .204, 205 and 206 are arranged to be heated in a well known manner by three batteries 242, 243 and 244 acting respectively'through rheostats 245, 246 and 247. The coil 239 forms the primary of a transformer 250, which has a secondar coil 251 arranged in a closed oscillatory circuit 252 which includes a variable condenser 253. The closed circuit 210 which controls the detector' 200 may be tuned to the natural frequency of oscillation of the open aerial circuit 215, 214 and 216, and the closed circuit 238, which is controlled by the detector 200, may be tuned to a predetermined secondary frequency. The closed circuit 252 may also be tuned to respond to the predetermined secondary frequency, and may be arranged to control a further detector or detectors or other devices forming a selective system constructed in any well known or suitable manner.

In this modified system, any suitable receiving device might be substituted for the two closed circuits 239 and 252 controlled by the detector 200. v

In the operation of the modified system shown in Fig. 6, the characteristic plate current-grid voltage curve of the detector 200 would be approximately the same as shown by the curved full line of Fig. 5, and the results obtained through the use of this modified system would be similar to the results obtained by the use of the system shown in Fig. 3 andehereinbefore described. In 'the modified form of this invention shown in Fig. 7, the construction is the same as that shown in Fig. 6, except that instead of the plurality of filaments 204 and the corresponding plurality of batteries,.a single elongated'filament 255 is provided which is arranged to be heated by battery 256 through a rheostat 257. One end of the filament is connected by a conductor 258 to one pole of a battery 259, the other pole of which is connected by a conductor 260 to one side ofthe hereinbefore described closed oscillatory circuit 238. By'having the filament 255 of a considerable and suitable length and of a suitable resistance, the normal heat current from the battery 256 in passing throughthe filament 255, will cause a predetermined drop in potential between one end of'thefilament and the other end of the filament, so that the different portions &

or saturate the improved detector than would be required where only a single detector of the ordinary form having a comparatively short filament, is used, and where the difference in voltage between the two ends of the filament is correspondingly small.

The ordinary audion or detector filament at its working temperature has a potential drop along its length of approximately two volts. The long, single filament hereinbefore described might at the proper temperature have a potential different of from six to ten volts between its terminals.

It is obvious that the means for postponing saturation herein described would be equally effective if the familiar stoppage condenser were employed in each of the grid leads of the audions.

Although only three forms have been shown herein in which this invention may be embodied, it is to 'be understood that the invention is not limited to any specific construction, but might be embodied in various systems without departing from the spirit of the invention or the scope of the appended claims.

Having thus fully described this invention, it claim:

1. A receiving system for radiant energy, comprising a receiving device, and a circuit for controlling said device, including two conductors and a plurality of detectors connected in parallel between said conductors, and a closed oscillatory circuit responsive to radiant energy and arranged to simultaneously control said detectors each or said detectors including a container and ionizing means. means for increasingly .varying the potential of the input circuit of each successive detector and a third electrode in said container.

2. A receiving system for radiant energy, comprising a receiving device, a circuit for controlling said device including two conductors and a plurality of gaseous delectors connected in parallel between said C01.- ductors, and a closed oscillatory circuit rcsponsive to radiant energy and arranged to simultaneously control said detectors each of said detectors including a container ling said receiving device, including a. closed oscillatory circuit provided with a con denser, two conductors leading from the opposite sides of said condenser respectively, and a plurality of detectors connected in parallel between said conductors each of said detectors including a container and ionizing means, i means for increasingly varying the potential of the input circuit of each successive detector and a third electrode in said container.

4. In a receiving system for radiant energy, a receiving circuit responsive to received radiant oscillations, an indicating device and a plurality of three-electrode thermionic tubes each having input and output elements, said tubes having their output elements connected to said indicating device, and means for applying progressively greater differences of potential to the input elements of the successive tubes.

5. In a receiving system for radiant energy, a receiving circuit responsive to received radiant oscillations, thermionic tube detecting means including an output circuit, a plurality of cathodes connected in parallel in the output circuit and means for controlling the passage of current through the detecting means in accordance with the received radiant oscillations, means for applying progressively varying differences in potential between the successive cathodes and said controlling means, and indicating means controlled by the output circuit.

6. In a receiving, system for radiant energy, a receiving circuit responsive to received radiant oscillations, thermionic tube detecting means including an output circuit, a plurality of cathodes connected in parallel in the output circuit and means for controlling the passage of current through the detecting means in accordance with the received radiant oscillations, sources of potential interposed between the cathodes for applying progressively greater differences in potential between the successive cathodes and said controlling means, and indicating means controlled by the output circuit.

I Signed at New York in the coimty of New York and State of New York-this 16th day of October. A. D, 1917.

JOHN HAYS HAMMOND, JR. 

